Adjustable order fault estimation observer based fault-tolerant control for switched fuzzy stochastic systems

Based on fault estimation, fault-tolerant control problem of switching stochastic nonlinear systems with actuator fault and sensor fault are studied. The fuzzy models are invited to solve the nonlinear problems of the systems. The fault estimation observer is designed to estimate the system states, actuator and sensor faults. The order of observer can be adjusted, which can improve the design flexibility and realize a compromise between the estimated cost and estimated accuracy. Unlike some classical results, the output differential is not required in the observer, which increases the application range. Based on the observer, the fault-tolerant controller is proposed, besides, the sufficient condition is achieved to ensure that the closed- loop system is mean-squared exponential stability. Finally, the feasibility is verified by two simulations.